1. Field of the Invention
The present invention relates to a valve system of an internal-combustion engine, in particular, it relates to an improvement of a support mechanism swingably supporting a rocker arm.
2. Description of the Related Art
Generally, in a valve system such as the above, a spherical projection formed on an adjusting screw provided on a rocker arm is supported by a concave support surface formed on a pivot fixed to a cylinder head, and is in slidable contact with the support surface as the rocker arm swings. Although lubricating oil is supplied between an outer surface of the spherical projection and the support surface, either or both of these surfaces suffer from abrasion because they are in metal-to-metal contact at certain points, and sludge resulting from this abrasion accumulates in the concave support surface. If the amount of accumulated sludge becomes excessive, this sludge will be forced into the areas in which the above two surfaces come in contact with each other, possibly causing abnormal abrasion of those surfaces.